The present invention relates to an electronic endoscope system and a light source for an endoscope for observing a color image of an object, and particularly to an electronic endoscope system and a light source for an endoscope suitably configured to allow an operator to observe a particular biological structure.
As a system for making a diagnosis on a body cavity of a patient, an electronic endoscope system is known and in practical use. Among such electronic endoscope systems, there is an electronic endoscope system configured to illuminate an object through a narrow band filter letting light with a certain wavelength band for which a particular biological structure shows a high degree of absorption pass therethrough, and to generate a spectral image highlighting the particular biological structure by receiving a scattered component of the light from the object, so that tissue information of the biological structure can be visualized.
In Japanese Patent Publication No. 3583731 (hereafter, referred to as patent document 1), an example of an endoscope apparatus for making an observation by narrow-band light is described. In the endoscope apparatus described in patent document 1, a narrow band filter configured to narrow a bandwidth of at least one of wavelength regions of illumination light is arranged on an optical path proceeding from an illumination light supply unit to an image pick-up unit and a band image of an object having a discrete spectral distribution obtained by the narrow-band light is generated. By using the endoscope apparatus of this type, it becomes possible to visually recognize tissue information of a particular biological structure of the object in a manner in which the tissue information is layered. As a result, tissue information at a desired depth in a tissue surface of the biological structure can be obtained.